Electric clock



W. E. PORTER ELECTRIC CLOCK Filed Dec. 1, 1928 2 Sheets-Sheet l April 22, 1930. w. E. PORTER I 1,755,560

ELECTRI C CLOCK f UNI ED ,STATES 2ORTEB, CF NEW HAVEN, CONNECTICUT, ASSIGN'OR TO THE NEW HAVEN CLOCKCO OF NEW -HAVEN', CONNECTICUT, A CORPORATION Patented Apr. 22, 1930 wrnson n.

ELECTRIC CLOCK Application filed December 1, 1928. Serial No. 323,047. 1

This invention relates to an improvement I in electric clocks and particularly to electric .clocks of the type in which a time-train is driven by a rotary'electric' motor.

The object of this invention is to provide at a low cost for manufacture a simple and reliable electric clock of the'typ'ereferred to 1 and constructed with particular reference to fewness of parts and to securing a step-by- I step movementof the hands in. simulation of the action of a standard clock having an esca ement-mechanism. v a

ith the above objectin view, my invention consists in an electric clock characterized by having asynchronous electric motor,

a time-train, pointers or hands driven by the said train, and an intermittent drive-mechanism interposed between the said motor and the said pointers so as to cause the former to efiect the stepby-step movement of the latter.

My invention further consists in an electric clock characterized as above and having cerilltain details of construction andcombinations of parts as willbe hereinafter described and particularly recited in the claims.

In the accompanying drawings:

Fig. 1 is a view in front elevation of an electric clock-movement constructed in accordance with my invention Fig. 2 is a side viewthereof Fig. 3 is a broken enlarged-scale sectional view taken on the line 33 of Fig. 1 and showing the second, minute, and hour hands in lace; and.

ig. 4; is a fragmentary perspective view of a portion of the two main elements of the intermittent driving-mechanism.

In the embodiment of my invention herein chosen for illustration, I employ a synchronous motor of welLknown characteristics and comprising the usual field 10 having a field coil 11 and a rotor 12 mounted upon a shaft 13 having hearing at its respective opposite ends in the forwardly-projecting arms 14 and 15 of a forwardly-facing U-shaped frame 16 secured by one or more screws 1| to the hackplate 18 of the clock-movement.

The synchronous motor just above referred to r uires no detailed description, since it is a welllmown article of commerce and is charcycles per second) and therefore provide an accurate governor for the speed of the synchronous motor. It follows that if the rotor 12 of the motor has imparted to it a predetermined constant speed that the ratios of the earin of the clock may be made such as to rive the hands at the required rate of speed to indicate the correct time of day.

The rear movement-plate 18 is of retangular form and has connected to it in spaced relation, by four pillars 19, a front movementplate 30 also of rectangular form and having its upper end notched as at 21 to accommodate the field 10 and field-coil 11 of the synchronous motor. The shaft 13 of the rotor 12 of the motor mounts a pinion 22 which is meshed into by the rearwardly-facing teeth 23- of a cupshaped crown-wheel 24 rigidly secured to an arbor 25 near the forward end thereof and hearing at its respective opposite ends in the rear and front movement-plates 18 and 20.

Near its rear end the arbor 25 above referred to has rigidly secured to it a disk 26 carrying an eccentrically-positioned forwardly-projecting drive-pin 27 adapted to engage in sequence the radial faces 28 of wedge-sha ed teeth 29 formed upon the periphery o a wheel 30 staked upon a shouldered collar 31 which in turn is rigidly attached to the center-arbor 32 of the timetrain. 7

The said center-arbor bears at its rear end in the rear movement-plate 18 and is formed at its front end with a forwardly-projecting slightly-tapered stem 33 hearing in the baseportion 34 of a'tubular stud 35 which is riveted into the front movementplate as at 36. The stem 33 of the centerarbor 32 has sleeved over it the tubular shank 3'7 of a secondhand 38. The tubular shank 37 of the second-hand serves to couple the latter to the center-arbor 32, so that the said hand will be moved synchronously with the same.

' bridge-plate 43 held in spaced relation with respect to the front movement-plate 20 by three pillars 44. I

Near its forward end the arbor 41 is provided with a pinion 45 meshing into and driving a minute-wheel 46 which is mounted upon the inner end of a minute-handsleeve 4'7 and frictionally coupled thereto by the tension of a spring'washer 48 also mounted upon the Sfllll sleeve and acting to force the said minute-wheel forward into frictional engagement with the rear face of a-cannon-pinion 49 formed integral with the minute-hand sleeve 47 aforesaid which latter rotates upon the exterior of the tubular stud This frictional coupling between the minutewheel 46 and the minute-hand sleeve 47 is i provided to permit the hands to be set without -moving the time-train proper.

The outer end of the minute-hand sleeve 47 carries, in the usual manner, a minute-hand Meshing into the cannon-pinion 49 so as to be driven therebyis a dial-whee1 51 mounted upon a stud 5:2.extending between the front movement-plate 20 and the bridge-plate 43 and carrying a dialpinion 53 meshing into an hour-wheel'54 staked upon the shouldered inner end of an hour-hand sleeve 55 rotating upon the periphery of the minute-hand sleeve 47 and carrying at its forwardend an hourhand 56. v

' To prevent the wheel 28 upon the centerarbor 32 from moving reversely with respect to the directionin which it has step by-step movement imparted to it by the drive-pin 27 I provide a detent-pin 57 adapted to engage the teeth of the said Wheel and mounted upon the outer end of a detent-arm 58 staked upon a staff 59 bearing at its opposite ends in the rear and front movement-plates 18 and 20 respectively. For the purpose of yieldingly holding the detent-pin 57 in engagement with the teeth of the Wheel 30 I mount upon the staff 59 of the detent-arm 58 a collar 60 carrying a s rin 61 h'avin its outer end restin a ainst a pin 62 projecting forward from the rear movementlate 18. The said spring exerts a constant e ort to hold the pin 57 in engagement with the teeth 29 of the Wheel 30.

As the pinion 22 is driven by the armature 12 of the synchronous motor it will follow that and its speed will be a constant one, owing to the fact that the said motor operates synchronously with the pulsations of the current a coming from a power station or other source of electrical energy.

During each revolution of the crown wheel 24 the eccentric drive-pin 27 Wlll ad vance the Wheel 30 one tooth in a clockwise direction as viewed in Fig. 1, thus effecting the step-by-ste rotation of the time-train and of the hands 88, 50 and 56 before described.

By employing avstep-by-step driving-mecl anism comprising the pin 27 and Wheel 30 for the time-train, I not only obviate the necessitv of a large number of gear-wheels to reduce the speed of the synchronous motor but also secure the highly desirable result of causing the movement of the hands to simulate in their step-by-step movement the action of the hands of a standard clock operating through an escapement-mechanism and to which the public are accustomed.

Furthermore; by employing the intcrmit tent drive for the time-train,- I am enabled to permit the synchronous motor to attain its required speed and thus avoid stalling owing to the fact that it'is free of appreciable restraint during a considerable number of revolutions. The motor meeting appreciable resistance only when the drive-pin 27 strikes one of the teeth 29 of the Wheel 30.

I claim:

1. In an electric clock having a continuously-rotating synchronous electric motor and visible time-indicating means driven there by; an intermittent step-by-step drive-mechanism interposed between the said motor and the said indicatingmeans; whereby the uniform rotary movement of the said motor is converted into a step-by-step movement of the said. timeindic ating means.

4 2. In an electric clock having a continuously-rotating synchronous electric motor and visible time-indicating means driven thereby;

. an intermittent step-by-step drive-mechanism interposed between the said motor and the said indicating-means and including a toothed wheel and an eccentric drive-member; whereby the uniform rotary movement of the said motor is converted into a step-hp step movement of the said time-indicating means.

In testimony whereof, I have signed this specification.

'WILSQN I 

